HB units will use Lakemaster and Navionics ...
The Navionics Regional cards were discontinued in 2015 ...
Currently the Navionics+ Preloaded and the Navionics Update cards have all the Nautical Charts for the US and Canada already on them.
You can add Sonar Charts locations of your choice. They are 16GB.
Navionics Update is a discount version of Navionics+ and takes a card you already own to activate it so it becomes the Navionics+ product.
You can view the current Navionics map data on their webapp here ...
http://webapp.navionics.com/?lang=en#@6&key=wfleFnz%60tQLakemaster cards are regional ... You can check which region your lakes are covered in here ...
http://www.humminbird.com/Category/Support/Find-a-Lake/Lakemaster adds a few map customization features that Navionics does not ...
Rickie